If the countered spell had {X} in its mana cost, include the value chosen for that X when determining how much mana to add to your pool. For example, if you counter a spell that costs {X}{R} with X equal to 5, you'll add six mana to your mana pool.

4/15/2013

Your precombat main phase is the main phase that happens immediately after your draw step, not any other main phase.